when the recirculate button is activated, vents from outside the front windshield open. air from the outside will enter the passenger cabin, and replace the old air with new air.

if the outside air is polluted, then the cabin air will also get polluted.
if the inside cabin air is foul-smelling, the outside air will replace this foul-smelling air.

if the outside air is hot, the aircon will have to work overtime, to cool the incoming hot air.

the manual said that??!!! are you sure?

heh heh.